Various surgical procedures require the distraction of two bones or other hard anatomical features. For example, a cervical laminoplasty procedure requires distraction of the lamina of the spine away from the lateral mass of the vertebra. FIGS. 1A-1C illustrate a cervical vertebra in various stages of a cervical laminoplasty procedure. With reference to FIG. 1A, a vertebra 100 with a compression of spinal cord 101. A distraction of the lamina is frequently initiated by cutting lamina 102 on one side of the vertebra to create a gap 103 in the lamina. An incomplete kerf 104 on the contralateral lamina may serve as a hinge. Distraction of the lamina increases the dimension of the gap 103, thereby elevating the lamina and opening the spinal canal, as shown in FIG. 1B. Distraction of the lamina can relieve spinal stenosis and pressure on the spinal cord 101 or surrounding nerve roots. As shown in FIG. 1C, an implant 105 may be placed in the enlarged laminar gap 103 following distraction and secured to the vertebra 100 using a plate 106.
An osteodistraction procedure can present risks to a patient. In a cervical laminoplasty, various common approaches to engaging and distracting the lamina present risks to the patient. The instruments that may be used, the force vectors and movements applied to the lamina using the instruments, and the manner in which they engage the surfaces of the bones involve risks of over-insertion and slippage, which can lead to direct and/or indirect trauma to the spinal cord. For example and as illustrated in FIGS. 2A and 2B, a curet 210 may be used to distract lamina 202 of vertebra 200. Curet 210 may first be inserted into laminar gap 203 (FIG. 2A). Such insertion involves directing curet 210 with force toward spinal cord 201, with a risk of overinsertion of curet 210 and injury to the spinal cord. Following insertion of curet 210 into laminar gap 203, curet 210 can be used to distract lamina 202, such as with a prying or lifting movement (FIG. 2B). Distraction using this or similar instruments and techniques presents a risk that lamina 202 will slip from the distraction instrument and return to its original position abruptly or forcefully and in an uncontrolled manner, causing injury to spinal cord 201.
The present disclosure provides systems and methods of osteodistraction that provide more predictable and/controllable distraction of two bone structures, thereby decreasing the risks to the patient associated with osteodistraction procedures.